Navigation Keys Quit Working After Workshee Change Macro

why my keyboard navigation keys (Tab and arrow keys) quit working after the code below executes? Other keyboard keys like alpha or numeric characters and Enter work but I can't move to another cell without clicking it. Selecting another ws, then returning to the "Master" ws fixes the problem. I tried activating Master near the end of the code but that didn't help. Master is not a protected sheet.

Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Column 7 Or Target.Cells.Count > 1 Then Exit Sub
If IsEmpty(Target) Then Exit Sub
Dim NextRow As Long, MySheet As Worksheet
Set MySheet = Sheets(Target.Value)
NextRow = MySheet.Cells(Rows.Count, 1).End(xlUp).Row + 1
With MySheet
.Unprotect "1234"
Range(Cells(Target.Row, 1), Cells(Target.Row, 6)).Copy .Cells(NextRow, 1)
With .Cells(NextRow, 7).......................................................